A qualitative model study on the effect of geosynthetic foundation reinforcement in sand overlying very soft clay

A centrifuge model study was carried out investigating the effects of the inclusion of geogrid reinforcement in a sand layer constructed over a thin, very soft clay layer to facilitate the construction of warehouse floors supporting product stockpiles. The use of geogrid reinforcement allowed larger surcharge loads to be applied for a given amount of settlement by allowing load to be spread over the footprint area of the geogrid due to the tension membrane effect and its associated benefits. A lower-bound calculation of the load at which the tensile reinforcement starts to function is presented. Upper-bound solutions were found to overestimate allowable surcharge loads, as they are associated with unacceptable deformations. The reinforcing effect of the geogrid was found to have been fully mobilised at 5% vertical compression of the clay layer.